izcain

Does anyone know of a calculator on the net or something where you can input the specs of your camshaft and have it tell you what the lift will be if you up rocker ratios from like 1.5 to 1.6 and such?
I'm lookin to up the lift with a ratio swap but lost the equations that help you determine the lift and such.

sofakingdom

iTrader: (1)

Use a regular calculator.

For SBC, the stock rocker ratio is 1.5.

If you're given the "theoretical valve lift", divide by 1.5 to get the lobe lift.

To figure out the lift with 1.6 rockers, mulitply the lobe lift by 1.6.

Or if you know the lift with 1.5 rockers, mulitply by 1.6/1.5 which is 1.066667, to get the new valve lift with 1.5 rockers.

Vader

Don't forget to calculate the slight increase in duration (at the valve) while your calculator is handy. You'll need some ramp data, or need to presume some data from the advertised duration, duration at 0.050" lifts, and know a little about the lift@° of the lobe.

You could try plugging some numbers into this, but it's not perfect:

Engine Calculator.xls